Asbestos is a naturally occurring fibrous mineral that was widely used in building materials from the 1950s to the 1990s. It was popular due to its heat-resistant properties and durability. However, it was later discovered that exposure to asbestos can cause a number of serious health problems. Asbestos fibers are extremely small and can be inhaled easily, leading to a number of respiratory diseases including lung cancer and mesothelioma. Asbestos has been banned in the UK since 1999, but many older buildings still contain asbestos-containing materials.